(a) Field of the Invention
The present invention relates to a display device. More specifically, the present invention relates to a demultiplexer for demultiplexing the data current in a display device.
(b) Description of the Related Art
FIG. 1 shows an active matrix organic light emitting diode (AMOLED) display device as an example of a current driven display device which needs current demultiplexing.
The current driven display device includes an organic electroluminescent (EL) display panel 100, a data driver 200 for providing a data current, a current demultiplexer 300 for performing 1:N demultiplexing on the data current, and scan drivers 400 and 500 for sequentially selecting a plurality of scan lines.
A predetermined data current is applied to pixels 10 coupled to scan lines selected by the scan drivers 400 and 500, and the pixels 10 display colors corresponding to the data current. A current demultiplex unit 300 is used so as to reduce the number of integrated circuits (ICs) of the data driver. That is, the current provided by the data driver 200 is 1:N-demultiplexed by the demultiplex unit 300, and is applied to the pixels corresponding to the N data lines data[1] to data[n]. Usage of the demultiplex unit 300 reduces the number of ICs necessary for the data driver and saves purchase costs.
FIG. 2 shows a conventional analog switch for a demultiplexer.
The 1:2 demultiplexer shown in FIG. 2 alternately switches the switches S1 and S2 to thereby output the data current to two data lines. A long time is required to program the data to the pixels 10 in order to realize high resolution in the current driven panel. When such conventional demultiplexing scheme is used to reduce the number of ICs of the data driver, however, the data programming time needs to be reduced since the data are to be programmed to the pixels each time the switches are alternately switched. Therefore, the conventional demultiplexer is not suitable for high-resolution display devices.